The near term physiological studies will focus on the spacio-temporal aspects of the responses of receptors considered to be involved in kinesthesia and proprioception. Psychophysical tests will be designed to reveal the contributions of the receptor responses in the sensation of position and motion of limbs, fingers and toes. The long-term objective of this research is to analyze and describe the proprioceptive system in quantitative terms by application of an engineering systems approach. Correlative physiological and psychophysical studies of proprioceptive systems will be undertaken. Clinical testing techniques based on the psychophysical methods and results will be used to bridge the gap between basic and clinical knowledge of proprioception. Signal detection theory will be used as a tool in the design and analysis of the psychophysical tests. Early physiological experiments will be confined to the receptor and dorsal column nuclei levels. Later in the project we propose to study the activity of cortical neurons in terms of spacio-temporal responses to the stimuli used in the receptor level studies. BIBLIOGRAPHIC REFERENCES: Heetderks, W. and Williams, W. Partition of Gross Peripheral Nerve Activity into Single Unit Responses by Correlation Techniques. Science, 188:373-375 (1975). Williams, W. and Porter, W. Some System Considerations of Neuron Pools with Feedback. Biol. Cybernetics, 21: 79-83 (1976).